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Wong" , Carlos Maiolino , Alexander Viro , Jan Kara , Christoph Hellwig , linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH RFC v4 2/3] iomap: use BIO_COMPLETE_IN_TASK for dropbehind writeback Message-ID: References: <20260325-blk-dontcache-v4-0-c4b56db43f64@columbia.edu> <20260325-blk-dontcache-v4-2-c4b56db43f64@columbia.edu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 49722140004 X-Stat-Signature: 54mzujeniz6yc8a4yzypuxwd36qqrihn X-Rspam-User: X-HE-Tag: 1774591405-380865 X-HE-Meta: U2FsdGVkX1/bPre5KYf/agWt+RVZiDvKUi5w491Uj5ONS4XAxCSLkXdjRgCr+sYrPm1KhPGPeWLpVewTw5i1cc9supHahjYpykoeOWjorempv0KAHzvfw+bUS75DTpWaA01OFQsqwvpbmldWVMY0oYvJuy+p5u8LdeoCnXjE7rs8Gn9b/PDHi6/WGi8K6HdvDY898fI3z43/tT4WL+B0rJMoUzC/zTqC1l7erlf/+neGwRHMJAgWvSSnuLr6HuntnY/6wShWeuZeXAv6hc9fKyZz5ECHDZpr8f3bPKfIoAKnGhkgrxyppUnUtQdx/qODRpTRzI25dDQndC6xnYuD4Xf9z9n+ytBVk+qL4VRstXhUfxEOWC+T+gNvERksmcRBZtPJ9gSIl0QdWyFvZ0QtgGx726VdnFBpHSbKy0GUusJhledrMA96rZ6hBuXFJHMZoFOUUtqXrmzoUwbb8ADy++xaEbdCjKW4LMIkfHQZdLsvHHB8lhWL4Edj5HIH4EUBXYFiumlopjaEOScr/L62lQsbS2gquBUNNSGWig1cW9y4WffQ2yffqSkPG2LK5WtVCBdj8dnQic9YcfR9dp4CjR/atYEkGROjsFhFyGdrWtbohIpr/+wJMw5ExIThhP4m8vyMuC06RIoWILWnKYamJu6Q1l07U3hGY+LGDQpyLETquki6VIuhyffuZjNKfEbrx71BnwgDfJ3qkSpJg5LP1F4txLU3xDpwpnrx6aXwb85rYSZMJjm3V1MOwBlVMGQnqxzcTK0dXzfxj8ePv9Y4IqmQ56pHZZPkUQQCegD6bpdv+kI4j3Cmise7qv0Hva/3xXZoF4V2uhUQcqX6564PUIqwxV9x/aJqqJCjqt4jbQIA52zrtgs/eqxDf/Md2+pqKZp9s6VYpbwi5xAQIEVnXLm3l6G4H5v5Cw66UmunTx8g5jjVl3zZU1wx5t9pAdaWt/BAnEbs+k5UhjIQ/Vh QERjWYPT 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Wed, Mar 25, 2026 at 08:21:28PM +0000, Matthew Wilcox wrote: > > + if (ioend_flags & IOMAP_IOEND_DONTCACHE) > > + bio_set_flag(bio, BIO_COMPLETE_IN_TASK); > > wbc_init_bio(wpc->wbc, bio); > > wpc->nr_folios = 0; > > return iomap_init_ioend(wpc->inode, bio, pos, ioend_flags); > > Can't we delete IOMAP_IOEND_DONTCACHE, and just do: > > if (folio_test_dropbehind(folio)) > bio_set_flag(&ioend->io_bio, BIO_COMPLETE_IN_TASK); > > It'd need to move down a few lines in iomap_add_to_ioend() to after > bio_add_folio() succeeds. Yes, that sounds sensible.